| 摘要 |
PURPOSE:To measure the flow rate of magnetic powder mixed fluid transported in a transport tube with high accuracy from the mixing ratio of magnetic powder and air for the transportation, the sectional area of the transport tube, and the flow velocity by applying a magnetic field at two positions in the flow direction of the transport tube, and detecting the time difference in the variation in magnetic permeability and finding the flow velocity. CONSTITUTION:Sensors 3 and 7 are provided at two specific positions in the lengthwise direction of the transport tube 1 and the magnetic field is applied crossing the pulverized coal fluid transported in the transport tube 1 by the air. The sensors 3 and 7 detect variation in the magnetic permeability of the pulverized coal flow crossing their sections to generate corresponding signals e1 and e2. A correlation signal processing circuit 11 outputs a flow velocity signal e3 based upon the generation time difference between the input signals e1 and e2 and the distance L between the two positions. A Gaussian meter 13, on the other hand, detects the density of magnetic flux by a Hall element 6 and outputs a signal e4 corresponding to the mixing ratio of the pulverized coal flow. A signal processing circuit 12 computes the weight flow rate of the pulverized coal flow on the basis of the input flow velocity signal e3, mixing ratio signal e4, and the sectional area of the transport tube 1 and outputs a corresponding signal e5.
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